A New Orbiting Deployable System for Small Satellite Observations for Ecology and Earth Observation

In this paper, we present several study cases focused on marine, oceanographic, and atmospheric environments, which would greatly benefit from the use of a deployable system for small satellite observations. As opposed to the large standard ones, small satellites have become an effective and affordable alternative access to space, owing to their lower costs, innovative design and technology, and higher revisiting times, when launched in a constellation configuration. One of the biggest challenges is created by the small satellite instrumentation working in the visible (VIS), infrared (IR), and microwave (MW) spectral ranges, for which the resolution of the acquired data depends on the physical dimension of the telescope and the antenna collecting the signal. In this respect, a deployable payload, fitting the limited size and mass imposed by the small satellite architecture, once unfolded in space, can reach performances similar to those of larger satellites. In this study, we show how ecology and Earth Observations can benefit from data acquired by small satellites, and how they can be further improved thanks to deployable payloads. We focus on DORA—Deployable Optics for Remote sensing Applications—in the VIS to TIR spectral range, and on a planned application in the MW spectral range, and we carry out a radiometric analysis to verify its performances for Earth Observation studies

PM 2.5 and PM 10 in the urban area of Naples: chemical composition, chemical properties and influence of air masses origin

In order to investigate particulate matter characteristics in the urban area of Naples, South of Italy, PM 10 and PM 2.5 chemical composition and properties were determined; in particular, ionic composition (Na + , K + , NH 4+ , Mg 2+ , Ca 2+ , HCOO-, CH 3 COO − , Cl − , NO 2− , NO 3− , SO 42− , C 2 O 42− ) and concentration of specific metals (Pb, Cd, Cu and Zn) were evaluated in association with an air masses trajectories study. Information on major ions was used to conduct the ionic balance and to evaluate sea salt and non-sea salt contributions; furthermore, the study on metals concentration allowed to distinguish the contribution of anthropic sources while their chemical behaviour (solubility and leachability) was considered in order to highlight the presence of different chemical forms. In the period of interest (June 2015), daily averages PM concentrations were below the limit of 25 μg/m 3 for PM 2.5 and 50 μg/m 3 for PM 10 ; moreover, for both fractions, the most abundant ionic species was SO 42− followed by NO 3− . Ionic balance indicated that non-sea salt contribution accounted for the great part of Ca 2+ , SO 42− and K + while secondary inorganic aerosol accounted for about 5% of total ionic fraction. As expected, the most abundant metal was zinc (about 41 ng/m 3 and 44 ng/m 3 in PM 2.5 and PM 10, respectively), while cadmium, copper and lead were at very low concentrations, in the range of 0.01–0.47 ng/m 3 ; leachability reached values of 40% for copper in both PM fractions, in contrast with zinc that showed the lowest leachability, corresponding to 6% for PM 2.5 fraction. The study on air masses trajectories indicated a change on ionic composition and chemical properties, varying from a condition with air masses coming from Eastern Europe, characterised also by higher concentrations of both PM 2.5 and PM 10 , a prevalence of secondary aerosol and metals showing minor solubility and leachability, to a condition with air masses coming from North-west region, with characteristics opposed to the previous ones

Emission factors of inorganic ions from road traffic: A case study from the city of Naples (Italy)

PM10 samples were collected in the urban tunnel of Naples (southern Italy) during a monitoring campaign on March 2015. Two sets of samples were collected at both sides of the tunnel, each set representing the daily cycle at a 1 h time resolution. Distance-based – mass per kilometer – emission factors (EFs) were calculated using mass concentrations, traffic flow rates and wind speed as a function of fleet composition. Samples were analysed for mass and water-soluble inorganic ions (Na+,NH4+,K+,Ca2+,Mg2+,Cl-,NO3- and SO42-) with the aim of investigating the influence of road traffic on the contribution of these species to PM levels. Road traffic directly emits inorganic ions, both from the exhaust and non-exhaust components. Analysis of ionic composition highlighted the increase in calcium concentration, which may derive from non-exhaust sources (road dust, wear of brake pads, clutches, tires) and calcium sulfonates, phenates or salicylates, often added to motor oils. Sulphate, added to lubricant oils, is also directly emitted at a rate higher than the gaseous sulphur dioxide emission. According to our analysis, nearly 10% of PM mass is composed by water-soluble inorganic ions, most of which directly emitted by automobiles. This suggests that an important contribution to PM emissions may derive from the inorganic component and more efforts should be devoted to constrain these emissions if PM concentration had to effectively comply with air quality standards

Size-segregated aerosol fluxes, deposition velocities, and chemical composition in an Alpine valley

The paper presents eddy covariance measurements of aerosol fluxes performed above an Alpine pasture in the Camonica Valley (Italian Alps) during summer 2019 and winter 2020. Vertical fluxes and deposition velocities (vds) were computed for nine aerosol size classes, with geometric mean diameters (GMDs) ranging from 10 nm to 0.76 μm, employing a fast-response electrical low-pressure impactor (ELPI+, Dekati, FI). At the end of each campaign, the concentration of water-soluble ions was estimated from the ion chromatography chemical speciation performed on the multi-impactor filters. K+ concentrations tripled in winter, evidencing the impact of biomass burning emissions, while nitrate, nitrite, ammonium, and sulphate were ascribed to secondary inorganic aerosol (SIA) formation. During summer, classes characterized by downward net daily fluxes presented a high percentage of SIA (> 70%) deposited on the respective filters. Phenomena of growth or coagulation of particles were also detected from the steady increase in concentrations during the day in classes with GMD ≥ 20 nm. Turbulence favoured intense aerosol exchange during the day. During summer nights, low friction velocities (u∗) led to weaker fluxes, while a strong, stable stratification in winter determined aerosol trapping at ground level and non-negligible, mostly negative, fluxes during nighttime. The trends of vds versus aerosol GMDs showed prevailing deposition phenomena under stable atmospheric conditions, with relative humidity higher than or equal to 90%, friction velocity lower than 0.15 m s−1, or wind speed lower than 2 m s−1. Cluster analysis identified groups of days with or without nucleation events and highlighted a rainout effect in summer during a period characterized by intense precipitation

Vertical transport of PM and PM and its source identification in the street canyons of Chennai metropolitan city, India

Chemical characterization of particulate matter (PM) measured along trafficked roads in Chennai city was performed during the winter season. Several heights, from 3 m to about 38 m above the ground level, and road geometries were taken into account. The daily average coarse (PM10) and fine (PM2.5) particles concentrations were in the range 72-110 (for PM10) and 34-57 mu g/m(3) (for PM2.5), depending on the site. Samples were analyzed in terms of inorganic ions using Ion Chromatography (IC) and elements by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results indicated the dominance of SO42- followed by Na+, Ca2+, NO3- and Cl- ions in the coarse fraction; similarly, in the fine fraction ion concentrations decreased in the following order: SO42-, NH4+, K+ and Ca2+. Among the elements, crustal element (Al, Fe) and Zn concentrations were much higher (accounting about 90% of the total elemental concentration) than other toxic elements (Cr, Cu, Mn, Ni, Pb, Sn, Ti and V). No element showed a significant dependence on height, expect for calcium at site 'Velachery' which contributed significantly to the abundance of the coarse fraction mass. In order to identify the major sources of air pollution, the collected data were analyzed using Positive Matrix Factorization (PMF), allowing to highlight five dominant pollution sources/factors: secondary PM, road traffic, biomass burning, sea spray and crustal erosion. Overall, the present study provided a new insight for the source apportionment of monitored pollutants in the Chennai city

Chemical characterisation of PM10 from ship emissions: a study on samples from hydrofoil exhaust stacks

A chemical characterization of PM10 collected at hydrofoil exhaust stacks was performed conducting two on-board measuring campaigns, with the aim of assessing the ship emission impact on PM10 collected in the coastal area of Naples (Southern Italy) and providing information about the characteristics of this important PM emission source.Samples were analysed determining the contribution of different chemical parameters to PM10's mass, which consisted of polycyclic aromatic hydrocarbons (PAHs) (0.10 ± 0.12%), total carbon (61.9% ± 20.0%, with 40.4% of organic carbon, OC, and 21.5% of elemental carbon, EC) and elemental fraction (0.44% ± 1.00%). Differences in terms of composition and chemical parameter profiles were observed between samples collected during offshore navigation (Off) and samples collected during shunting operations (SO), the latter of higher concern on a local scale. For SO samples, lower contributions of OC and EC were observed (39.7% and 19.6% respectively) compared to Off samples (41.5% and 24.2%), and an increase in terms of elements (from 0.32 to 0.51%) and PAHs (from 0.06 to 0.12%) concentrations was observed. In addition, enrichment factors (EFs) for some elements such as V, Zn, Cd, Cu, Ag and Hg as well as PAHs profile varied significantly between SO and Off. Data presented here were compared with data on chemical composition of PM10 sampled in a tunnel, in a background site and in an urban site in the city of Naples. Results indicated that shipping activities contributed significantly to the emission of V and, in some extent, Zn and Cd; in addition, PAH profiles indicated a greater contribution to urban PM10 from vehicular traffic than shipping emissions. These results can significantly contribute to the correct evaluation of the influence of shipping emission on PM10 generation in urban coastal areas and can be a useful reference for similar studies. The coastal area of Naples is an important example of the coexistence of residential, touristic and natural areas with pollutants emission sources including, among the others, shipping emissions. In this and similar contexts, it is important to distinguish the contribution of each emission source to clearly define environmental control policies

Inter-comparison of carbon content in PM2.5and PM10collected at five measurement sites in Southern Italy

A field campaign was performed simultaneously at five measurement sites, having different characteristics, to characterize the spatial distribution of the carbonaceous content in atmospheric aerosol in Southern Italy during the winter season. Organic carbon (OC) and elemental carbon (EC) were measured at urban (Naples), suburban (Lecce), coastal/marine (Lamezia Terme and Capo Granitola), and remote (Monte Curcio) locations. OC and EC mass concentrations were quantified by the thermal-optical transmission (TOT) method, in 24-h PM10and PM2.5samples collected on quartz fiber filters, from 25 November 2015 to 1 January 2016. The different sites showed marked differences in the average concentrations of both carbonaceous species. Typically, OC average levels (±standard deviation) were higher at the sites of Naples (12.8 ± 5.1 and 11.8 ± 4.6 μg/m3) and Lecce (10.7 ± 5.8 and 9.0 ± 4.7 μg/m3), followed by Lamezia Terme (4.3 ± 2.0 and 4.0 ± 1.9 μg/m3), Capo Granitola (2.3 ± 1.2 and 1.7 ± 1.1 μg/m3), and Monte Curcio (0.9 ± 0.3 and 0.9 ± 0.3 μg/m3) in PM10and PM2.5, respectively. Similarly, EC average levels (±standard deviation) were higher at the urban sites of Naples (2.3 ± 1.1 and 1.8 ± 0.5 μg/m3) and Lecce (1.5 ± 0.8 and 1.4 ± 0.7 μg/m3), followed by Lamezia Terme (0.6 ± 0.3 and 0.6 ± 0.3 μg/m3), Capo Granitola (0.3 ± 0.3 and 0.3 ± 0.2 μg/m3), and Monte Curcio (0.06 ± 0.04 and 0.05 ± 0.03 μg/m3) in PM10and PM2.5, respectively. An opposite trend was observed for the OC/EC ratios ranging from 6.4 to 15.9 in PM10and from 6.4 to 15.5 in PM2.5with lower values in urban sites compared to remote sites. Different OC-EC correlations, 0.36 < R2< 0.90, were found in four observation sites. This behavior suggests the contributions of similar sources and common atmospheric processes in both fractions. No correlations were observed between OC and EC at the site of Naples. The average secondary organic carbon (SOC) concentrations, quantified using the minimum OC/EC ratio method, ranged from 0.4 to 7.6 μg/m3in PM10and from 0.4 to 7.2 μg/m3in PM2.5, accounting from 37 to 59% of total OC in PM10and from 40 to 57% in PM2.5with higher percentages in the urban and suburban sites of Naples and Lecce

Particulate Matter Ionic and Elemental Composition during the Winter Season: A Comparative Study among Rural, Urban and Remote Sites in Southern Italy

We present an overview of the concentrations and distributions of water-soluble ion species and elemental components in ambient particulate matter for five measurement sites in southern Italy with the aim of investigating the influence of the different site characteristics on PM levels. The sites encompass different characteristics, ranging from urban to coastal and high-altitude remote areas. PM10 and PM2.5 fractions were collected simultaneously using dual channel samplers during the winter period from November 2015 to January 2016 and analyzed for water-soluble ion species, using ion chromatography, and elemental composition, using inductively coupled plasma mass spectrometry (ICP-MS). In all sites, PM2.5 represented the higher contribution to particulate mass, usually more than two times that of the coarse fraction (PM2.5−10). At the coastal site in Capo Granitola (Western Sicily), sea salts constituted about 30% of total PM10 mass. On average, ion species accounted for 30% to 60% of total PM10 mass and 15% to 50% of PM2.5 mass. We found that secondary ion species, i.e., SO2−4, NO−3 and NH+4 dominated the identifiable components within both PM2.5 and PM10 fractions. The chlorine–sodium ratio was usually lower than that expected from the natural level in sea salt, evidencing aged air masses. At the monitoring site in Naples, a highly urbanized area affected by high levels of anthropogenic source emissions, an increased contribution of ammonium was found, which was imputed to the increased ammonia emissions from industrial combustion sources and road traffic. The concentrations of the investigated elements showed noteworthy differences from one site to another. The PM10 fraction was highly enriched by sources of anthropogenic origin in the samples from the most urbanized areas. In general, the enrichment factors of the elements were similar between the PM10 and PM2.5 fractions, confirming common sources for all element